Integrated die bumping process

ABSTRACT

An integrated die bumping process includes providing a load board, defining a plurality of die regions on a surface of the load board for placing dice of a plurality of die specifications, affixing a plurality of dice respectively on the die regions according to the plurality of die specifications, and performing a die bumping process.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 10/905,490filed Jan. 6, 2005, and incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a die bumping process, and more particularly,to an integrated die bumping process which integrates dice of differentdie specifications on a same load board for simultaneously performing adie bumping process.

2. Description of the Prior Art

The flip-chip technology is an advanced semiconductor fabricationtechnology that allows the overall package size to be made very compact.The flip-chip package configuration differs from conventional onesparticularly in that the semiconductor chip is mounted in an upside-downmanner on a substrate and electrically coupled to the same by means ofsolder bumps provided on the active surface of the semiconductor chip.Since no bonding wires are required, the overall size of the flip-chippackage can be made very compact as compared to conventional types ofpackage configurations. Therefore, it is a trend recently to manufacturesemiconductor chips with wafer bumping processes.

During the early development stage before semiconductor chips massproduction, different semiconductor chips to be manufactured utilize asilicon shuttle service provided by United Microelectronics Corp. (UMC).Silicon shuttle service is capable of manufacturing dice of differentuses and specifications on a same wafer simultaneously to reduceproduction costs and shorten the cycle time. However, semiconductorchips that require die bumping processes of the flip-chip packageconfiguration are not well suited for being manufactured by the siliconshuttle service since the respective mask expenses of wafer bumpingprocesses need to be considered. If these semiconductor chips furtherperform wafer bumping processes or single die bumping separately aftercompleting silicon shuttle service and dicing, higher costs, morecomplicated processes and longer cycle times will be needed, and thebump size will be restricted.

SUMMARY OF THE INVENTION

It is therefore a primary objective of the present invention to providean integrated die bumping process to solve the above-mentioned problems.

According to the objective of the present invention, an integrated diebumping process of the present invention includes providing a loadboard, defining a plurality of die regions on a surface of the loadboard for placing dice of a plurality of die specifications and each dieregion therein used to place a plurality of dice of a same diespecification, affixing a plurality of dice respectively on the dieregions according to the plurality of die specifications, and performinga die bumping process. The integrated die bumping process furtherincludes a leveling step when the dice on each die region have differentthickness to make the bump pads of each die affixed on each die regionbe located on the same level, and a step that forms a plane layer on theload board surface where the load board surface is not covered by thedice after completing the step of affixing the dice.

Since the present invention integrates dice taken from different wafers,formed by different manufacturing processes, and requiring the flip-chippackage configuration on a same load board to perform a die bumpingprocess, semiconductor chips that require wafer bumping processes of theflip-chip package configuration are suited to be manufacture by thesilicon shuttle service to reduce production costs, mask expenses ofwafer bumping processes and shorten the cycle time.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a load board surface of an integrateddie bumping process according to the present invention.

FIG. 2 to FIG. 7 are schematic diagrams for illustrating an integrateddie bumping process according to a first embodiment of the presentinvention.

FIG. 8 and FIG. 9 are schematic diagrams for illustrating an integrateddie bumping process according to a second embodiment of the presentinvention.

DETAILED DESCRIPTION

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a load boardsurface of an integrated die bumping process according to the presentinvention. As shown in FIG. 1, a surface of a load board 10 according tothe present invention has a plurality of die regions 12-31 defined forplacing dice of a plurality of die specifications. Each die region 12-31is used to place a plurality of dice of a same die specification. Thedie specifications mentioned above include factors such as diethickness, die size, the quantity of the bump pads, the disposedlocation of the bump pads, or any combination of the above.

Please refer to FIG. 2 to FIG. 7. FIG. 2 to FIG. 7 are schematicdiagrams for illustrating an integrated die bumping process according toa first embodiment of the present invention. As shown in FIG. 2, a loadboard 40 is provided. The load board 40 is a glass substrate, whichoffers good support and heat conducting characteristics. However, thepresent invention is not restricted to using glass substrates. Otherload boards with the same functions may be applied in the presentinvention, such as a semiconductor wafer, quartz, and a metal board. Asurface of the load board 40 includes a sticking layer 42 and is defineda plurality of die regions 41, 43, and 45 for placing dice of aplurality of die specifications. The sticking layer 42 is selected fromthe group consisting of B-stage epoxy, blue tape, twin adhesive tape,ultraviolet adhesive tape, thermal curing adhesive tape, photoresist,and wax, and utilizes spin coating, sticking, and depositing to form onthe surface the load board 40.

As shown in FIG. 3, a plurality of dice 44, 46, and 48, which are takenfrom a same wafer or different wafers, or formed by a same manufacturingprocess or different manufacturing processes, are placed in an arrayconfiguration and affixed respectively on the die regions 41, 43, and 45according to the corresponding die specifications. For the sake ofsimplicity, figures in the following text only display a single die.Surfaces of the dice 44, 46, and 48 all include a plurality of bump pads50, and the present invention may further perform a leveling step beforeaffixing the dice 44, 46, and 48 respectively on the die regions 41, 43,and 45 according to the corresponding die specifications, such asgrinding the lower surfaces of the dice 44, 46, and 48 to make the dice44, 46, and 48 have a same thickness, and then to make the bump pads 50of the dice 44, 46, and 48 affixed on the die regions 41, 43, and 45 belocated on the same level. The leveling step is favorable for thefollowing processes.

Please refer to FIG. 4. The sticking layer 42 is cured to firmly affixthe dice 44, 46, and 48 on the surface of the load board 40 after thedice 44, 46, and 48 are disposed on the die regions 41, 43, and 45.Then, the portion of the load board 40 that is not covered by the dice44, 46, and 48 has a plane layer 52 formed on it by spin coating ordepositing. The plane layer 52 is made of benzocyclobutene (BCB) orpolyimide (PI). Then, a cure process is performed to firmly affix theplane layer 52.

As shown in FIG. 5, a die bumping process is performed. A dielectriclayer 54 is formed on the surface of the load board 40 to cover eachbump pad 50. A plurality of contact holes 56 are formed by aphotolithography and etching process in the dielectric layer 54 andcorresponding to each bump pad 50 location to expose each bump pad 50.An under bump metallurgy (UBM) process is performed to form a metallayer 58 on the surface of each bump pad 50 in each contact hole 56.

As shown in FIG. 6, a plurality of solder bumps 62 are formed on eachmetal layer 58 corresponding to the location of each contact hole 56 byutilizing a mask 60, which is made before the step of defining the dieregions, and a solder printing process. The mask 60 is made according tothe die regions on the load board planned in advance, the dice on eachdie region, and the bump pad location on each die. Therefore, a patternof the mask 60 corresponds to the die regions of different diespecifications.

It is to be noted that the step of manufacturing the mask 60 also couldbe executed after the step of affixing the dice 44, 46, and 48. Forexample, the mask 60 is formed after scanning the load board 40 with thedice 44, 46, and 48 affixed on it, and the pattern of the mask 60corresponds to the dice 44, 46, and 48 on the load board 40. Moreover,the solder bumps 62 also could be formed by utilizing a mask made inadvance and a thin-film, photolithography, etching process, and solderelectroplating or printing. Similarly, the step of manufacturing themask could be executed before or after the step of affixing the dice 44,46, and 48.

As shown in FIG. 7, the mask 60 is removed, a reflow process isexecuted, and then the die bumping process is finished. After finishingthe die bumping process, the present invention further includes acutting process to separate the dice 44, 46, and 48.

FIG. 8 and FIG. 9 are schematic diagrams for illustrating an integrateddie bumping process according to a second embodiment of the presentinvention. The difference between the first embodiment and the secondembodiment of the present invention is the leveling step. As shown inFIG. 8, according to different die thickness, a plurality of bottomlayers 76 and 78 of different thickness are formed on surfaces of thedie regions 72 and 74 on the load board 70.

As shown in FIG. 9, a plurality of dice 82 and 84 has different diethickness and the lower surfaces of the dice 82 and 84 have a stickinglayer 80. The dice 82 and 84 are affixed on the bottom layers 76 and 78on the surface of the die regions 72 and 74. Therefore, a plurality ofbump pads 86 of the dice 82 and 84 affixed on the die regions 72 and 74are located on the same level.

Since the present invention integrates dice taken from different wafers,formed by different manufacturing processes, and requiring the flip-chippackage configuration on a same load board to perform a die bumpingprocess, semiconductor chips that require wafer bumping processes of theflip-chip package configuration are suited to be manufactured by thesilicon shuttle service for reducing production costs and mask expensesof wafer bumping processes and for shortening the cycle time.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

1. An integrated die bumping process comprising: providing a load boardand a mask including a pattern on a surface; utilizing the pattern ofthe mask to define a plurality of die regions on a surface of the loadboard for placing dice of a plurality of die specifications, wherein thedie specification comprises die thickness, die size, the quantity of thebump pads, the disposed location of the bump pads, or any combination ofthe above, and a surface of each of the dice comprises a plurality ofbump pads; utilizing a sticking layer to affix a plurality of dice oneach die region according to the corresponding die specification;forming a plane layer on the load board surface where the load boardsurface is not covered by the dice after completing the step of affixingthe dice, wherein the surface of the plane layer is even with thesurface of the dice; forming a dielectric layer on the surface of theload board and a dielectric layer covering on each bump pad; utilizingthe mask to perform a photolithography and etching process for formingat least a contact hole in the dielectric layer and exposing each bumppad; performing an under bump metallurgy process to form a metal layeron the surface of each bump pad and in each contact hole; and forming asolder bump on the metal layer corresponding to the contact holelocation.
 2. The integrated die bumping process of claim 1, wherein theload board is a glass substrate.
 3. The integrated die bumping processof claim 1, wherein each die region is used to place a plurality of diceof a same die specification.
 4. The integrated die bumping process ofclaim 1, wherein the plurality of dice affixed on each die region isplaced as an array.
 5. The integrated die bumping process of claim 1,wherein the sticking layer is selected from the group consisting ofB-stage epoxy, blue tape, twin adhesive tape, ultraviolet adhesive tape,thermal curing adhesive tape, photoresist, and wax.
 6. The integrateddie bumping process of claim 1 further comprising a leveling step, whenthe dice on each die region have different thickness, to make the bumppads of each die affixed on each die region be located on the samelevel.
 7. The integrated die bumping process of claim 1, wherein thedice are taken from different wafers and formed by differentmanufacturing processes.
 8. The integrated die bumping process of claim1, wherein the method of forming the plane layer is a spin coatingprocess and the material of the plane layer is benzocyclobutene (BCB) orpolyimide (PI).
 9. The integrated die bumping process of claim 1 furthercomprising a cutting process for separating each die after completingthe die bumping process.
 10. An integrated die bumping processcomprising: providing a load board and a mask including a pattern on asurface; utilizing the pattern of the mask to define a plurality of dieregions on a surface of the load board for placing dice of a pluralityof die specifications, wherein the die specification comprises diethickness, die size, the quantity of the bump pads, the disposedlocation of the bump pads, or any combination of the above, and asurface of each of the dice comprises a plurality of bump pads; forminga plurality of bottom layers having different thickness on the dieregions of the load board; utilizing a sticking layer to affix aplurality of dice on each bottom layer; forming a plane layer on theload board surface where the load board surface is not covered by thedice after completing the step of affixing the dice; and forming adielectric layer on the surface of the load board and a dielectric layercovering on each bump pad; utilizing the mask to perform aphotolithography and etching process for forming at least a contact holein the dielectric layer for exposing each bump pad; performing an underbump metallurgy process to form a metal layer on the surface of eachbump pad in each contact hole; and forming a solder bump on the metallayer corresponding to the contact hole location.